1. Field of the Invention
The present invention relates to an electronic brake pedal adjustment apparatus and, more particularly, to a device and method for setting braking characteristics, for enabling the driver to set the desired braking operation for a given brake pedal pressure within a safe range.
2. Description of the Prior Art
Vehicular brake pedal adjustment apparatuses that have been previously proposed include the electronic brake pedal adjustment apparatus, which comprises a sensor related to the brake pedal effort or brake pedal travel and a sensor related to the brake fluid pressure or vehicle deceleration, detects vehicle brake pedal pressure and calculates the desired brake fluid pressure using a computer, and adjusts the brake fluid pressure by a brake pressure controller.
Conventional electronic brake pedal adjustment apparatuses such as the above are intended, for example, to compensate for changes in the brake stroke effectiveness due to the carried load or the .mu. (coefficient of friction) of the friction material, or to obtain a stronger braking pressure with less strength required for brake operation or with a lighter pedal stroke. In any case, however, the brake designer sets the relationship between the brake pedal pressure or brake pedal travel and the brake fluid pressure, i.e., set the braking characteristics.
The present inventor has also proposed an apparatus using an electronic brake pedal adjustment apparatus to resolve the problem of the driver needing to continuously depress the brakes while stopped by automatically applying the brakes even after the brake is released, but only when it is confirmed from the detection signals from each of the sensors that the intention of the driver is to remain stopped. (Japanese Patent Laid-open Publication No. 59-18054)
Many recent vehicles enable the driver's seat to be adjusted in many ways, including front-back position, seat angle and height, and steering wheel position, thus allowing the driver to select the best positions for his/her height and physique.
Despite these various adjustments, it is still difficult for many drivers, who must use both the brakes and the steering wheel, to obtain a suitable combination of braking effect (brake fluid pressure) with respect to the applied braking force (brake pedal effort) because of the fixed position of the brake pedal and/or the fixed relationship between the brake pedal effort and the brake fluid pressure (vehicle deceleration).
The recent trend has also been towards brakes that can assure sufficient braking when operated with little effort, and towards brakes that can assure sufficient braking when operated with a short pedal travel.
It must be noted, however, that while many drivers like these trends as revealed in a survey conducted by the present inventors, there are small numbers of drivers that are not satisfied, feeling either that the trends have either not gone far enough or have already gone too far.
This dissatisfaction cannot be resolved even by using current electronic brake pedal adjustment apparatuses whereby the brake designer can freely set the braking characteristics.
The electronic brake pedal adjustment apparatus described in Japanese laid-open Patent No. 59-18054 reflects the intent of the driver in the braking characteristics, but is nothing more than a means for detecting, using sensors while the vehicle is stopped, whether the driver intends to remain stopped, and for automatically generating the brake pressure to keep the vehicle stopped; it does not propose a means enabling the driver to set the braking characteristics as desired while also in motion.